Linerless closure cap

ABSTRACT

A linerless closure cap formed of a plastic material which includes an end panel and a depending skirt, said end panel having an exterior planar facing surface and an interior facing surface, said end panel having an annular U-shaped groove facing outwardly with said groove being in general vertical alinement with said skirt portion, said inwardly facing surface having an annular sealing surface extending inwardly of the inner portion of said skirt and sloping inwardly and downwardly, said inwardly facing surface having an annular groove positioned adjacent the inner end of said annular sealing surface, said inclined annular sealing surface adapted to be compressed to assume a generally horizontal planar surface when said closure cap is tightened against the mouth of the container, said pair of annular grooves forming hinge means to permit deflection of said end panel when said closure cap is in sealing position.

United States Patent [1 1 Gerk June 10, 1975 LINERLESS CLOSURE CAP [75] Inventor: Richard G. Gerk, Palos Park, Ill. [57] ABSTRACT [73] Assignee: VCA Corporation, Baton Rouge, A linerless closure cap formed of a plastic material La. which includes an end panel and a depending skirt, [22] Filed, sepL 19 1973 said end panel having an exterior planar facing surface and an interior facing surface, said end panel having i PP fi an annular U-shaped groove facing outwardly with said groove being in general vertical alinement with 52 11.5. C1 215/344; 215/317 Said said inwadly P surface hams 51 Int. Cl 865d 53/02 Sealmg emndmg. "l 58 Field of Search 215/344 345 341 343 i' sbpmg l 3 downwardly, said inwardly faclng surface having an annular groove positioned adjacent the inner end of [56] References Cited said annular sealing surface, said inclined annular sealing surface adapted to be compressed to assume a UNITED STATES PATENTS generally horizontal planar surface when said closure 2,586,775 2/1952 Benner 2l5/34l ap is tightened against the mguth of the container 3,255,903 6/1966 5 1 215/344 said pair of annular grooves forming hinge means to permit deflection of said end panel when said closure Primary Examiner-Herbert F. Ross Attorney, Agent, or FirmMax R. Kraus cap is in sealing position.

8 Claims, 5 Drawing Figures LINERLESS CLOSURE CAP BRIEF SUMMARY OF THE INVENTION The prior art discloses linerless plastic closures which are provided with annular grooves forming hinging means for the end panel of the caps, however, in those instances where the annular grooves both face inwardly into the interior of the closure, the outermost annular groove adjacent the skirt of the closure leaves an annular recess which prevents the effective sealing of said closure in relation to the mouth of the container. The present invention aims to obviate this objectionable characteristic by providing a closure cap with a pair of annular grooves whereby the end panel of said closure has a pair of hinging means but one of said annular grooves faces outwardly of the top panel so as not to interfere with the annular sealing surface of said closure. With this invention the advantages of a double hinge end panel is obtained without in any way affecting the sealing surface of said closure.

Another object of this invention is to provide a linerless plastic closure cap which may be injection molded and is constructed from a plastic material such as copolymeric thermoplastic material which may be polypropylene. polyethylene or polystyrene.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevational view of the exterior of the cap forming this invention.

FIG. 2 is a central cross-sectional view of the cap.

FIG. 3 is an enlarged fragmentary sectional view of the cap and the neck of the container to which it is applied.

FIG. 4 is a view similar to FIG. 3 with the cap screwed into closure position; and

FIG. 5 is a reduced top plan view of the cap.

The linerless closure cap constructed in accordance with this invention, as illustrated in the drawings, is generally designated at 10, said closure cap being a one-piece construction and preferably formed from copolymeric thermoplastic material such as polypropylene, polyethylene or polystyrene by the conventional injection molding process.

The linerless closure cap includes an end panel generally designated at 12 and a depending integral peripheral skirt 14 which is tapered or inclined outwardly as at 16 from the top towards the bottom, with the exterior surface provided with vertically extending spaced ribs 18 for gripping purpose. The interior of the skirt is provided with a continuous screw thread 20 forming the means for securing the closure cap to an associated container 22, and when the closure cap 10 is tightened for sealing purpose, as shown in FIG. 4, an axial force is created which is sufficient to deflect a portion of the end panel 12, as will be hereinafter described.

The end panel 12 includes an outer facing surface 24 and an inner facing surface 26 defining therebetween a predetermined wall thickness in which the annular portion 28 of the wall adjacent the skirt has a greater thickness than the thickness of the central circular wall portion 30 of the closure cap. The central circular wall portion 30 and the annular wall portion 28 are joined to each other by annular hinge means generally designated at 32 and sometimes herein referred to as the first hinge means. Said annular hinge means 32 is formed by a reduction in the thickness of the wall of the panel by means of an axially downwardly opening annular groove 34.

A second hinge means generally designated at 36 is formed by an axially outwardly opening annular groove 38 which is positioned substantially in vertical alinement with the skirt portion 14 and spaced inwardly of the peripheral corner edge 39 of the closure cap. The annular wall portion 28 forms on the underside thereof the annular sealing surface 40. The two annular grooves 34 and 38 are in coaxial relationship with each other, but the groove 34 faces inwardly into the interior of the cap while the groove 38 faces outwardly or exteriorly of the cap.

The annular sealing surface 40 which faces inwardly into the interior of the closure cap is at an inclined angle of approximately 10 and it extends from adjacent the inner wall of the skirt 14 to and below the vertical side wall 42 of the groove 34 and is coextensive with said vertical wall. The end panel 12 has its thickest portion, indicated at 44, adjacent the vertical side 42 of the groove 34 and the central portion 30 of the panel would have the thinnest wall thickness. The outer end of the sealing surface 40 which merges with the inside vertical wall of the skirt has a slight radius, indicated at 46, and the innermost portion of the sealing surface which merges into the vertical side wall 42 of the inwardly facing groove 34 also has a slight radius, indicated at 48.

Referring to FIGS. 3 and 4, the container 22 includes a conventional upstanding neck 50 having an exterior screw thread 52 and a peripheral lip 54 which is generally planar. After the container has been filled with a product, the closure cap I0 is applied and is rotated to tighten it with respect to the neck of the container the inwardly inclined sealing surface 40 of the closure cap engages the flat lip 54 of the container and as the cap is tightened the annular sealing surface 40 comes into complete sealing contact with the container lip, as shown in FIG. 4. During the downward movement of the closure cap as it is being tightened the end panel 12 temporarily deforms to the configuration shown in FIG. 4 by virtue of the two hinge means 32 and 36 which permit the annular wall portion 28 and the circular central wall portion 30 to deflect upwardly in the manner clearly illustrated in FIGv 4. During this deflection the underside of the annular sealing surface 40 assumes a horizontal or planar condition and completely covers the annular lip 54 of the container to effect positive sealing over the entire surface of the lip of the container, and when the sealing surface 40 is compressed to the horizontal position as shown in FIG. 4, a portion of said sealing surface flexes so that the portion indicated at 56 extends into the mouth of the container. The annular wall portion 28 and the central wall portion 30 also flex slightly upwardly from their normal FIG. 3 position to the sealing closure position shown in FIG. 4. This produces an effective seal between the closure cap and the lip of the container.

With this invention there is provided a closure cap with a pair of hinge means which effectuates a perfect seal with the lip of a container and eliminates the loss of a portion of the sealing surface which heretofore resulted with the prior structures.

What is claimed is:

l. A linerless closure cap formed of a plastic material and adapted for sealing engagement with an associated container in which the linerless closure cap comprises an end panel and a depending peripheral annular skirt, said peripheral skirt having means for securing the closure cap to a container, said end panel having an outwardly facing surface and an inwardly facing surface facing inwardly into said closure cap. said outwardly facing surface having an annular groove extending into said end panel and formed adjacent the peripheral edge but spaced therefrom and in substantial vertical alinement with the skirt to provide a second hinge means. said inner facing surface of said end panel having an annular sealing surface which is adjacent said annular skirt and extending inwardly and downwardly at an angle, another annular groove formed in the underside of said top end panel and extending into said end panel and facing inwardly in the direction of the interior of said closure cap to provide a first hinge means, said inwardly facing groove being adjacent the innermost portion of said annular sealing surface, said pair of hinge means permitting flexing of said end panel at said hinge means, said annular inclined sealing surface adapted when the closure cap is in sealing position to be compressed to assume a seal-tight engagement with the entire top edge of the container.

2. A structure as set forth in claim 1 in which the end panel has an annular outer surface and a central annular surface, and in which the annular outer surface has a greater thickness than the thickness of the central annular surface, with said sealing surface formed on the underside of said annular outer surface.

3. A structure as set forth in claim 1 wherein the inclination of the outer annular sealing surface is approximately 10 relative to a plane normal to the closure axis.

4. A structure as set forth in claim 1 in which the inwardly facing annular groove is of a generally U-shaped configuration and has an outer vertical wall which con tinues below the plane of the opposite inner wall of said groove, which outer vertical wall of said groove merges into the downwardly inclined sloping sealing surface.

5. A structure as set forth in claim 1 in which said outwardly facing annular groove and said inwardly facing annular groove are each of a generally U-shaped configuration.

6. A structure as set forth in claim 1 in which said pair of hinge means causes said end panel to deflect upwardly as said closure cap is tightened to closure posi tion.

7. A structure as set forth in claim 1 in which the outwardly facing surface of the end panel of the closure has a horizontal planar surface when the closure cap is not secured to the container in a sealing position.

8. A structure as set forth in claim 1 in which the in nermost portion of the inclined sealing surface adjacent the inwardly facing groove extends inwardly into the mouth of the container when the closure cap is in sea]- tight engagement with the container. 

1. A linerless closure Cap formed of a plastic material and adapted for sealing engagement with an associated container in which the linerless closure cap comprises an end panel and a depending peripheral annular skirt, said peripheral skirt having means for securing the closure cap to a container, said end panel having an outwardly facing surface and an inwardly facing surface facing inwardly into said closure cap, said outwardly facing surface having an annular groove extending into said end panel and formed adjacent the peripheral edge but spaced therefrom and in substantial vertical alinement with the skirt to provide a second hinge means, said inner facing surface of said end panel having an annular sealing surface which is adjacent said annular skirt and extending inwardly and downwardly at an angle, another annular groove formed in the underside of said top end panel and extending into said end panel and facing inwardly in the direction of the interior of said closure cap to provide a first hinge means, said inwardly facing groove being adjacent the innermost portion of said annular sealing surface, said pair of hinge means permitting flexing of said end panel at said hinge means, said annular inclined sealing surface adapted when the closure cap is in sealing position to be compressed to assume a seal-tight engagement with the entire top edge of the container.
 2. A structure as set forth in claim 1 in which the end panel has an annular outer surface and a central annular surface, and in which the annular outer surface has a greater thickness than the thickness of the central annular surface, with said sealing surface formed on the underside of said annular outer surface.
 3. A structure as set forth in claim 1 wherein the inclination of the outer annular sealing surface is approximately 10* relative to a plane normal to the closure axis.
 4. A structure as set forth in claim 1 in which the inwardly facing annular groove is of a generally U-shaped configuration and has an outer vertical wall which continues below the plane of the opposite inner wall of said groove, which outer vertical wall of said groove merges into the downwardly inclined sloping sealing surface.
 5. A structure as set forth in claim 1 in which said outwardly facing annular groove and said inwardly facing annular groove are each of a generally U-shaped configuration.
 6. A structure as set forth in claim 1 in which said pair of hinge means causes said end panel to deflect upwardly as said closure cap is tightened to closure position.
 7. A structure as set forth in claim 1 in which the outwardly facing surface of the end panel of the closure has a horizontal planar surface when the closure cap is not secured to the container in a sealing position.
 8. A structure as set forth in claim 1 in which the innermost portion of the inclined sealing surface adjacent the inwardly facing groove extends inwardly into the mouth of the container when the closure cap is in seal-tight engagement with the container. 